Revert "Show dialog if top app is killed by lmk"

This reverts commit ac7bbb840b8edc04a21af381d7dfbd9a57c9af15.

Comments in ag/3029299 for more details.

Bug:65488249
Test: manual

Reason for revert: No mechanism to check if an app is killed because of low memory killer

Change-Id: I3e461c241c5e30bdfc9b528a70939522180083c9
3 files changed